Finding the Fourth Proportional to 1,442.98, 1,991.37 and 813.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,442.98 : 1,991.37 = 813.53 : x
2. Step 2: Convert to fraction form
   1,442.98/1,991.37 = 813.53/x
3. Step 3: Cross multiply
   1,442.98x = 1,991.37 × 813.53
4. Step 4: Simplify right side
   1,442.98x = 1,620,044.21
5. Step 5: Solve for x
   x = 1,620,044.21/1,442.98
6. Step 6: Final answer
   x = 1,122.71